Currently as a MS student in the process of applying to Ph.D. programs I included undergraduate presentations/publications on my CV. This included presentations done at my institution (annual university research conference), national conferences, and summer research programs. For the purposes of applying to Ph.D. programs depending on your discipline, you want to include every presentation/publication that is relevant to the program that you are applying to for graduate school even if this includes stuff done as a ug or master's student. Regarding the "selected publications" section on your CV, this would only come into play when you are applying for post-doc positions, but if you don't have any publications then whatever you have should suffice until you build up your selection.
I hope that this helps:-)